Older Calendar Items Delete Automatically

[DadOD]

I have a Treo 700w and sync it to Outlook via a Windows Vista computer. It all seems to be working fine… except calendar items older than two months or so delete themselves!
Is there a setting somewhere in Windows Mobile calendar that directs the calendar to automatically delete older appointments items?
I have narrowed the source of this problem to the Treo when I sync it to my Outlook. I’ve added a older appointments in Outlook and then upon syncing with the Treo I’ve watched the calendar appointments delete themselves. I have the calendar settings under Windows Mobile Device Center set to sync “All past appointments”.
I’d want to stop the auto deletion. Can anyone tell me where the setting might be that will stop this auto deletion?
Thanks.